Add s3 example for glacier objects

boto3/examples/s3.rst

@@ -12,3 +12,33 @@ the objects in the bucket.
     bucket = s3.Bucket('my-bucket')
     for obj in bucket.objects.all():
         print(obj.key)
+
+
+Restore Glacier objects in an Amazon S3 bucket
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The following example shows how to initiate restoration of glacier objects in
+an Amazon S3 bucket, determine if a restoration is on-going, and determine if a
+restoration is finished.
+
+.. code-block:: python
+
+    import boto3
+
+    s3 = boto3.resource('s3')
+    bucket = s3.Bucket('glacier-bucket')
+    for obj_sum in bucket.objects.all():
+        obj = s3.Object(obj_sum.bucket_name, obj_sum.key)
+        if obj.storage_class == 'GLACIER':
+            # Try to restore the object if the storage class is glacier and
+            # the object does not have a completed or ongoing restoration
+            # request.
+            if obj.restore is None:
+                print('Submitting restoration request: %s' % obj.key)
+                obj.start_restore()
+            # Print out objects whose restoration is on-going
+            elif 'ongoing-request="true"' in obj.restore:
+                print('Restoration in-progress: %s' % obj.key)
+            # Print out objects whose restoration is complete
+            elif 'ongoing-request="false"' in obj.restore:
+                print('Restoration complete: %s' % obj.key)